Method of coking and classifying particulate matter by fluidization



W. PETERS ET AL 3,419,474 METHOD oF COKIN@ AND CLASSIFYING PARTICULATE Dec. 31, 196s MATTER BY FLUIDIZATION Flled July 9 1964 INVENTORS /Q me l" /DRJB ATTORNEY United States Patent O 3,419,474 METHOD F COKING AND CLASSIFYING PAR- TICULATE MATTER BY FLUIDIZATION Werner Peters, Langacker 5, Wattenscheid-Hontrop, Germany, and Kurt-Christian Traenckuer, Grosser Schirnkamp 15, Essen-Steele, Germany Filed July 9, 1964, Ser. No. 381,586 Claims priority, application Germany, Sept. 24, 1963, B 73,630; Dec. 5, 1963, B 74,544 11 Claims. (Cl. 201-4) ABSTRACT 0F THE DISCLOSURE A coking method, comprising the steps of introducing into the lower portion of an elongated upright tubular reaction vessel a suspension in a hot gas of coal particles adapted to be coked, the hot gas serving as substantially the sole source of heat for coking the -coal particles, so as to form inthe reaction vessel a stream consisting of the particles dispersed in hot gas and upwardly passing throughout substantially the entire length of the tubular reaction vessel in such a manner as to cause during the upward passage of the stream through the tubular reaction vessel coking of the coal particles and formation of a hot combustible gas thus converting the upwardly owing stream during passage of the latter through the tubular reaction vessel into a suspension of coked particles in combustible gas, withdrawing the suspension from the upper portion of the tubular reaction vessel, and Separately recovering from the withdrawn suspension the coke and the combustible gas thereof.

The present invention relates to a coking method and device and, more particularly, the present invention is concerned with producing coke dross, i.e. coke having a particle size of up to about mm.

Coke dross is obtained as a by-product of the conventional coke production due to the abrasive action of the larger coke particles. However, recently the commercial demand for coke dross has increased to such an extent that additional coke dross is now produced by grinding of larger coke particles. This process, however, is highly uneconomical.

It is therefore an object of the present invention to provide a simple and economical manner of producing coke dross.

It is another object of the present invention to provide apparatus for producing coke dross in a simple and economical manner.

It is yet another object of the present invention to provide a coking method whereby the coke will -be immediately formed in the size range of coke dross.

Other objects and advantages of the present invention will become apparent from a further reading of the description and of the appended claims.

With the above and other objects in view, the present invention contemplates a coking method comprising the steps of forming an upwardly flowing stream of a mass of particulate coal adapted to be coked, having a particle size up to about l0 mm. and dispersed in gas having a temperature of at least 200 C. so as to cause during such upward flow of the stream coking of the particulate coal under formation of hot combustible gas, and separately recovering the combustible gas and the thus formed coke.

The present invention also includes a coking arrangement comprising, in combination, an elongated upright coking tube, introduction means associated with the lower end of the coking tube for introducing particulate coal into the same, blowing means Iassociated with the lower end of the coking tube for blowing hot air into the same 3,419,474 Patented Dec. 3l, 1968 ice so as to form in the coking tube an upwardly flowing suspension of coal particles in hot air thereby causing in the coking tube coking of the coal particles and formation of combustible gas, withdrawal means associated with the upper end of the coking tube for withdrawing the suspension of coke and combustible gas therefrom, and separating means operatively connected to the withdrawal means for separating the suspension into coke particles and combustible gas.

According to the present invention, coke dross is produced in Ia simple and economical manner by blowing coal which is adapted to be coked and which has a particle size of up to about 10 mm., by means of preheated air and at the speed of at least about 3 meters per second, in upward direction, through an upwardly, preferably vertically, extending coking tube having a length of at least 3 to 5 meters. Thereby, due to the degassing and combustion process which will take place during passage of the coal-air mixture through the coking tube, a maximum temperature will be reached within the coking tube which will be at least equal to about 750 C. Coke dross and hot combustible gases will be formed in the tube and will leave through the upper end thereof. The thus produced coke dross is then separated from the combustible gases and the latter may be utilized for various purposes.

According to the present invention, it is possible to cause degasication of coal up to a particle size of about 10 mm. in a very quick manner and so that a coke dross is formed having approximately the same particle size as the initially introduced coal. The combustible gases formed during the coking process will have, depending on the quality of the starting material, a caloric value of up to about 3,000 kcal. per standard cubic meter.

The coal is conveyed through the upright coking tube by means of air blown in to the lower end of the coking tube and preheated to at least 200 C. However, it is also possible to replace the air with other gases and particularly to introduce in combination with air or other gases a relatively small proportion of combustible gases into the lower portion of the coking tube. The passage of the coalgas suspension through the coking tube, during which passage the suspension is changed into a suspension of coke in combustible gas, is facilitated by having the interior of the coking tube completely unobstructed.

The speed of flow of the gases through the upright coking tube will be adjusted to the particle size of the coal which is to be coked. Relatively small sized coal having a particle size of up to 3 mm. preferably will be blown through the coking tube in a gas stream having a speed of at least about 5 meters per second. Larger size coke particles up to a particle size of about 10 mm. require a correspondingly higher speed of flow of the gas, up to about 30 meters per second. The particulate coal is introduced into the coking tube from below, preferably pneumatically in a manner known per se. Depending on the desired yield yper unit of time, the :inner diameter of the coking tube will be preferably between 0.5 meters and 3 meters, most preferably between 0.80 meters and 1.80 meters. It is possible to coke between 20 and 40 metric tons of `coal per hour in a coking tube having a length of l0 meters and an inner diameter of 1.50 meters. The air-coal ratio should be so chosen that at least 500 standard cubic meters of air are blown into the tube for each metric ton of coal and at most about 1000 standard cubic meters of air should be introduced for each metric ton of coal. Generally, the optimum ratio will be about 700 stand-ard cubic meters of air per metric ton of coal.

Depending on the specific operating conditions, particularly the quality of the coal, the temperature within the coking tube may rise -up to about l350 C., whereby either a completely or a partially degaszsed coke dross is produced. As starting material any coal may be used which contains at least about 14% of volatile constituents.

The coke dross which leaves the coking tube at the upper end thereof can be easily separated not only from the hot stream of combustible gas, but also into several fractions of coke dross diiiering by size. Thus, for instance, the coke dross leaving the upper end of the coking tube may .be separated into a fraction containing smaller particles of a size, for instance, of up to 5 and into a fraction containing larger particles having a size of between about 5 and 10 mm. In order to utilize the sensible heat of the thus produced hot coke dross, the same may be passed through various types of cooling, i.e., heat exchange devices such as fluidized bed coolers, drop coolers or tube coolers.

It is also within the scope of the present invention to admix the still hot coke dross to moist briquetting coal. Thereby, due to evaporation of water, the moisture content of the briquetting mixture will be reduced and possibly also the content of volatile constituents of the briquetting mixture. Furthermore, the combustible waste gases emanating from the coking tube may be utilized without purification for operating a drying device for the drying of briquetting coal.

In addition, the coke dross produced according to the present invention may be used, either hot or after cooling, for mixing with strongly baking or fat coal so as to form a somewhat leaner mixture which is better suitable for subsequent coking. In this connection, it is also possible to use the combustible gas as it emanates from the coking tube and without purification for operating a drying installation for the drying or preheating of the usually moist coking coal.

Furthermore, the freshly produced coke dross may be advantageously used as the sintering fuel for the sintering of ore and the like. In this case it is also advisable to charge the sintered belt with the coke dross without prior cooling of the latter in order to utilize the sensible heat of the coke dross.

In cases where the coke dross produced according to the present invention is used as fuel for the sintering of Ore or the like, it is furthermore advantageous to utilize the lhot combustible gases emanating from the coking tube for the igniting of the coke dross-ore or the like sintering mixture. Thus, it is particularly advantageous to combine the coking method of the present invention with a sintering process.

In cases where the above described or other particularly advantageous utilizations of the hot combustible gases are not available, the separated combustible gases may be used as heating gas, for instance for producing steam.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings in which the figure is a schematic elevational view of a coking device in accordance with the present invention.

Referring now to the drawing, it will be seen that preheated air may be introduced through conduit 2 into heat-insulated coking tube 1, while the finely particulate coal having a particle size of up to l mm. is pneumatically blown into the lower end of coking tube 1 through conduit 3. At the upper end of coking tube 1, a mixture of coke dross and of a tar and water-containing combustible waste gas will leave the coking tube. The larger coke dross particles are separated in separator 5 and the smaller coke dross particles in separator while the combustible gas which thus has been freed of coke dross is withdrawn through conduit 4.

The larger coke dross particles are cooled while passing through cooler 7, by means of water sprinklers 6 so that coke dross having a temperature of about 150 C. collects in hopper 8 provided with a suitable gate at its lower end from which the coke may be dropped into hopper car 9.

The liner coke dross particles will pass from cyclone separator 10 through sluice gate 11 into Water cooler 12 and from there to hopper 13 and eventually into hopper car 14.

The heat balance of the method of the present invention is highly favorable. By coking a highly volatile coal, about 65% of the calories of the initial coal are retained in the coke dross and 30% can be found in the combustible waste gas, so that the entire caloric loss of the degasification amounts only to about 5% A coking tube of 10 meter length and an inner diameter of 1.5 meters has a capacity such that -generally about 30 tons per hour of gasilame coal, i.e. a fat coal containing between about 32 and 36% of volatile constituents can be degasitied therein. Thus, the yield per unit of cross sectional area of the coking tube of the present process is at least about 5 times greater than that obtainable in the conventional iiuidized bed coking process.

The following examples are given as illustrative only, the present invention, however, not being limited to the specilic details of the examples.

EXAMPLE l 30 tons of a fat coal containing 38% of volatile constituents and having a particle size of between 0 and 6 mm. are passed together with 23,000` standard cubic meters of air preheated to 450 C., at a speed of 15 meters per second through a coking tube having a length of 16 meters and a diameter of 1.40 meters. Thereby, a maximum temperature of between 1000 and 1100 C. will be reached in the coking tube. 14.4 metric tons of coarse coke dross and 4.2 metric tons of iine coke dross are recovered as well as 29,000 standard cubic metersof waste gas having a caloric value of 2,500 kcal. per standard cubic meter. The waste gas passing through conduit 4, without ybeing subjected to purification, is introduced into a heating device, for instance a steam boiler.

According to the present example the air which is introduced through conduit 2 has been preheated to 450 C. Generally, depending on operating c-onditions, the air will -be preheated to between 200 and 500 C.

EXAMPLE 2 1000 kg. of fat coal containing 25% volatile constituents and having a particle size of between 0 and 3 mm., dispersed in 700 standard cubic meters of air which have been preheated to 350 C. are passed at a speed of iiow of 12 meters per second through a coking tube having a length of 12 meters and a diameter of 1 meter. The temperature in the coking tube reaches between 900 and 1200 C. 720 kg. of coke dross containing 12% volatile constituents and having a temperature of 600 C. are obtained and are mixed while still hot with 600 parts by weight of a briquetting coal having a water content of 15%. The temperature of the thus obtained mixture will be about C. and the water content thereof will be practically nil. The thus formed mixture is excellently suitable to be briquetted in conventional mauner.

EXAMPLE 3 1000 kg. of a slightly baking coal containing 18% of volatile constituents and having a particle size of from 0 to 2 mm., are passed together with 550 standard cubic meters of air preheated to 400 C., at a speed of 12 meters per second through a coking tube having a height of 6 meters and a diameter of 80 cm. The maximum degassing temperature reached in the coking tube is about 850 C. By proceeding in a continuous manner, there are obtained per hour 850 kg. of coke dross containing 6% of volatile constituents. The thus obtained coke is excellently suitable for forming a somewhat leaner mixture with strongly baking coking coal.

EXAMPLE 4 By passing 1000 kg. of a coal containing 45% of volatile constituents and having a particle size of from -8 mm. together with 900 standard cubic meters of air preheated to 400 C. through a coking tube having a diameter of 2.50 meters and a length of 22 meters, 600 kg. of coke dross are obtained.

The thus obtained coke dross contains l0% volatile constituents and is mixed with 15 times its own `weight of a fine iron ore and the thus formed mixture is placed on a sintering belt. The combustible waste gas formed in the coking tube and separated from the coke dross serves in part for operating the ignition stove of the sintering device. Excess waste gas is used for heating purposes, for instance in a steam boiler. In this manner, with a relatively small amount of coke dross, a high quality sintered product is obtained.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of coking devices difiering from the types described above.

While the invention has been illustrated and described as embodied in a coking arrangement incuding an upright tubular coking tube, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specic aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A coking method comprising the steps of introducing into the lower portion of an elongated upright tubular reaction vessel having a diameter of between about 0.5 and 3 meter a suspension in hot air of coal particles adapted to be coked, said hot air having a temperature of at least 200 C. and serving as substantially the sole source of heat for coking said coal particles and being present in said suspension in an amount of between about 500 and 1000 standard cubic meters for each metric ton of coal particles, so as to form in said reaction vessel a stream consisting of said particles dispersed in hot air and upwardly passing throughout substantially the entire length of said tubular reaction vessel at a velocity of between about 5 and 30 meters per second, in such a manner as to cause during said upward passage of said stream through said tubular reaction vessel coking of said coal particles and formation of a hot combusti-ble gas thus converting said upwardly owing stream during passage of the latter through said tubular reaction vessel into a suspension of coked particles in combustible gas; withdrawing said suspension from the upper portion of said tubular reaction vessel; and separately recovering from said withdrawn suspension the coke and the combustible gas thereof.

2. A coking method as defined in claim 1, wherein said upright tubular reaction vessel extends in substantially vertical direction, and the amount of hot air per metric ton of coal particles equals about 700 standard cubic meters.

3. A coking method as defined in claim 1, wherein said coal particles adapted to be coked have a .maximum size of up to l0 mm.

4. A coking method as defined in claim 1, wherein said upright tubular reaction vessel is an elongated substantially vertical reaction tube having a length ofiat least 3 meters, said coal particles have a size of up to 10 mm., said hot air having a temperature of between about 200 C. and 500 C., and said stream passing through said vertical reaction tube at a speed of at least 3 meters per second. f

5. A coking method as defined in claim 4, wherein said reaction tube has a length of between about 3 and l0 meters, said stream passes therethrough at a speed of between 3 and 30 meters per second, and said preheated air has a temperature of between about 200 and 500 C.

6. A coking method as defined in claim 5, wherein said preheated air is present in said stream in an amount equal to between about 500 and 1000 standard cubic meters per metric ton of said coal particles.

7. A coking method as defined in claim 1, wherein a mass consisting of larger and smaller coal particles is pneumatically introduced into the lower portion of said upright tubular reaction vessel together with said hot air so as to form said upwardly passing stream in said tubular reaction vessel 8. In a briquetting method the steps of coking coal particles and separately recovering coked particles as defined in claim 4, and including introducing the thus recovered coke particles while still hot into a moisturecontaining briquetting mixture. l

9. In a coal-drying method, the steps of coking coal particles and separately recovering the thus formed coke particles and hot combustible gas, as defined in claim 4, and including contacting moist coal with said separately recovered hot combustible gas so as to heat and dry said coal.

10. In an ore sintering method the steps of coking coal particles and separately recovering the thus formed coke particles and hot combustible gas, as defined in claim 4, and including forming a mixture of thus recovered hot coke and an ore adapted to be sintered; and sintering said ore in the presence of said hot coke.

11. A method, as defined in claim lll), wherein at least a portion of said separately recovered combustible gas is burned for heating said mixture of coke and ore.

References Cited UNITED STATES PATENTS 288,550 11/1883 Coombes 209--139 393,411 11/1888 Willis 209-143 1,475,502 11/1923 Manning 201-31 1,888,372 11/1932 Bramwell 209-139 2,339,932 1/ 1944 Kuhl 201-31 3,011,953 12/1961 Foch 201-37 3,053,648 9/1962 Stephens et al. 75-26 3,117,918 l/l964 Batehelor et al 201-6 3,140,240 7/ 1964 Fowler 201--31 3,150,958 9/1964 Collin et al. 75-36 NORMAN YUDKOFF, Primary Examiner.

A. EDWARDS, Assistant Examiner.

U.S. Cl. X.R. ZCI- 31, 39 

